<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .nav li {
      color: red;
    }

    /* 需求把第一个小li  颜色改为 粉色加粗 */
    /* .one   权重是10  .nav .one  20 */
    .nav .one {
      color: pink;
      font-weight: 700;
    }
  </style>
</head>

<body>
  <ul class="nav">
    <li class="one">人生四大悲</li>
    <li>家里没狗带</li>
    <li>网速不够快</li>
    <li>手机流量少</li>
    <li>学校没wifi</li>
  </ul>
</body>

</html>